Natural resources, key components in food production, have become increasingly limited. Therefore, it is urgently necessary to optimize production methods and agricultural inputs, such as pesticides and other agrochemicals, to ensure successful production and thereby safeguard food security for Mexico population (FAO, 2017). Mexico is characterized by its gastronomic diversity, with the following ingredients and raw materials standing out due to their high production volumes and yields: grain corn (Zea mays), beans (Phaseolus vulgaris), sorghum (Sorghum spp.), oats (Avena sativa), and forage corn. However, the crops that generate the greatest economic output are corn, green pepper, red tomato, sorghum, and beans (SIAP, 2021). It is worth noting that the states with the largest harvested agricultural area in 2024 were Zacatecas, Tamaulipas, Chiapas, Jalisco, and Puebla, while those generating the highest economic output were Sinaloa, Jalisco, Michoacán, Sonora, and Chihuahua (SIAP, 2026).

The slogan for the 2021 World Food Day, established by FAO, is: “Our actions are our future.” By generating bioproducts obtained from the production chain of fruits and vegetables itself, it is possible to achieve a degree of sustainable, sufficient, and safe production, with adequate nutritional quality and accessible to all. It is important to consider all these factors to ensure sustainable agriculture; however, meeting all these objectives represents a major challenge (FAO, 2021).

Current figures indicate that around 690 million people worldwide suffer from hunger, representing nearly 9% of the global population, with a trend that continues to rise (UN, 2021). The growing world population is a challenge that puts agro-production systems to the test. It is estimated that by 2030, the population will reach 6 910 million in developed countries, while in developing countries, it will reach 381 million. By 2050, global population growth is projected to reach 9 322 million, with an annual increase of 0.6%; this means that 1.4% more agricultural food will be required to meet the daily caloric needs of an adult (3 050 kcal/capita/day). Therefore, it is necessary to implement efficient strategies for the production and management of insect and phytopathogenic pests, as they can cause losses of up to 20% of total production (CIPF, 2021). Although chemical pesticides are useful and effective for preventing and eradicating pests, they have, since their introduction, caused a series of serious environmental and public health impacts, in addition to inducing resistance in crops and contaminating groundwater and soil, among other effects documented in literature. Therefore, it is important to seek efficient alternatives that take environmental impact and toxicity into consideration (Bapat et al., 2022; Moustafa et al., 2021; Tang and Luo, 2021).

According to the Corporate Statistical Database of the Food and Agriculture Organization of the United Nations, the main agricultural products produced in 2024 were sugarcane (Saccharum officinarum) (1 939 782 021 t), maize (1 218 205 574 t), and rice (820 223 278 t) (Figure 2). The countries with the highest production volumes were China, Brazil, and the United States (FAO, 2026). These production volumes generate substantial quantities of by-products composed of fibers, peels, seeds, bagasse, roots, leaves, stems, and other lignocellulosic materials rich in phytochemicals, which have high value-added commercial implications (Nayak and Bhushan, 2019; Teigiserova et al., 2019).

Figure 2

FC derived from agro-industrial by-products, used as biopesticides, have been widely studied and exhibit a broad range of applications (Figure 3). For example, in the Web of Science (Clarivate) database, at least 931 original publications have been recorded in the last 10 years. However, most of these studies use medicinal plants or edible fruits as sources of FC. Among them, aromatic plants (rich in essential oils) lead chemical and biological research, mainly due to their bactericidal and antifungal activity.

On the other hand, the leading countries in this area of research are the United States, China, and India. It is worth noting that, only ≈588 documents on the extraction of phytochemicals from agro-industrial by-products, with Italy, Spain, and Portugal being the countries with the highest number of publications. Of these, only a small number focus on plant health, making it of interest to expand research to enhance the use of these underutilized resources for crop health and, consequently, for human and environmental health. In this context, incorporating practices such as the use of biopesticides as part of integrated management of major pests and diseases generates a circular economy model that produces biopesticides from crude extracts or purified metabolites obtained from crop-generated by-products, contributing to the shift from a linear to a circular economy and implementing differentiation strategies that support competitiveness in the agricultural sector (Campos et al., 2020; Rojas Rojas et al., 2021).

Figure 3

The presence of phytopathogenic organisms and the diseases they cause can be influenced by biotic and abiotic factors during sowing, vegetative and productive stages, harvest, and postharvest of crops. Among the biotic factors, fungi, bacteria, viruses, protozoa, and nematodes stand out. However, the most abundant and economically significant phytopathogens are fungi, viruses, and bacteria, which are responsible for most phytosanitary problems worldwide and, consequently, for the greatest economic and food losses (Ravichandra, 2013). The bacterial genera associated with severe diseases that result in major crop losses and have the greatest economic relevance include: Acidovorax, Agrobacterium, Bacillus, Burkholderia, Citrobacter, Clavibacter, Dickeya, Erwinia, Leifsonia, Pectobacterium, Pseudomonas, Ralstonia, Spiroplasma, Xanthomonas, and Xylella, among others (Hernández-Díaz et al., 2021; Setubal et al., 2005). On the other hand, the most extensively studied fungal genera are Alternaria, Botrytis, Colletotrichum, Fusarium, Drechslera (Syn. Helminthosporium), Aspergillus, Penicillium, Macrophomina, Neofusicoccum, Rhizoctonia, Sclerotinia, Curvularia, Mucor, Botryosphaeria, Diplodia, Sclerotium, and Phoma (Di Canito et al., 2021; Hernández-Díaz et al., 2021; Xu et al., 2021). Knowledge of these phytopathogenic agents allows for the effective study and application of biocontrol strategies.

Pest management is based on the principles of prevention, suppression, and/or eradication, and each of these can involve different strategies-biological, chemical, mechanical, cultural, genetic manipulation, among others (Zepeda-Jazo, 2018). Among the most widely used and effective tools against all types of pests are chemical pesticides; however, toxic side effects on humans, flora, fauna, and various ecosystems continue to be documented, as agrochemicals can migrate hundreds of kilometers and affect distant regions (Couvidat et al., 2022; Degrendele et al., 2022; Ding et al., 2022). In response, governments are working to create alternatives that reduce or replace their use. In contrast, regarding the phytotoxicity of natural extracts, high doses may desiccate plants, but when applied at the doses recommended by producers, no toxic effects have been reported in humans or other mammals (Fenibo et al., 2022).

Phytochemicals (FC). Phytochemicals (FC) are secondary metabolites synthesized through the shikimic acid, malonic acid, and mevalonic acid pathways, and it is estimated that more than 100,000 exist; however, those most extensively studied due to their bioactivities are flavonoids, terpenes, alkaloids, and saponins (Figure 4) (de la Rosa et al., 2019; Khare et al., 2020). The accumulation of phytochemicals in plants is generally associated with stress conditions caused by biotic and abiotic factors, which trigger a cascade of biochemical signals that primarily promote their synthesis as a defense mechanism (Marranzano et al., 2018). Since ancient times, humans have used and commercialized FC for therapeutic purposes to treat a wide variety of diseases and ailments. With technological advances and increasing awareness of environmental protection, FC have been studied to demonstrate their biocidal potential against phytopathogens, among other applications, such as additives, pigments, and antioxidant agents. Phenolic compounds can exhibit a wide variety of structures and are therefore classified from simple phenolics to highly complex phenolics, depending on the number and position of hydroxyl groups attached to the phenolic ring (Chaudhary et al., 2018; Singh et al., 2017). Within this group of FC are flavonoids, phenolic acids, coumarins, lignins, and tannins. Flavonoids are recognized as the most important and widely distributed in plants, with more than 5,000 reported. These compounds are of low molecular weight; their structure contains two aromatic rings of phenolic nature linked by a three-carbon bridge (C6-C3-C6). They are divided into different subgroups, such as flavonols, flavanones, flavones, flavan-3-ols, isoflavones, catechin, leucoanthocyanidins, chalcones, and anthocyanins (Lattanzio, 2013; Medina-Meza and Ganjyal, 2017; Tsao, 2010).

Figure 4

On the other hand, terpenes are hydrophobic organic compounds derived from the condensation of isoprene (a five-carbon hydrocarbon). Based on this, they can be categorized as hemiterpenes (C5), monoterpenes (C10), sesquiterpenes (C15), diterpenes (C₂₀), sesterterpenes (C₂₅), triterpenes (C₃₀), tetraterpenes (C₄₀), and polyterpenoids (C_>40). Among the tetraterpenoids are the carotenoids; β-carotene, in particular, is highly relevant because it is the precursor of vitamin A. In this sense, some vitamins are considered terpenes, such as the fat-soluble vitamins D and K (Pichersky and Raguso, 2018).

Methods for the extraction and purification of phytochemicals from agricultural and agro-industrial by-products. Extraction methods for FC rely on their ability to degrade cellular structures, such as walls and membranes, and to subsequently solubilize the FC in the extraction solvent. Depending on the hydrophilicity or hydrophobicity of the molecules of interest, a solvent of similar polarity is used, following the solubility principle: “like dissolves like.” Therefore, most FC are solubilized in organic solvents such as ethanol, methanol, or water. For example, flavonoids can be extracted with 70-80% hydroethanolic solutions, methanol, or acetone, whereas carotenoids and other nonpolar compounds, such as fats and oils, dissolve in hexane, toluene, and methylene chloride, among others (Jiménez-Ortega et al., 2024).

The extraction method will largely depend on the yield and purity of the compound. Currently, systems such as temperature-controlled maceration, ultrasonic baths, microwaves, supercritical fluids, ionic and eutectic solvents (DES), and hydrogenated solvents, among others, can be employed. Their advantage is that these techniques can be coupled, resulting in higher extraction yields while reducing energy consumption and operating time (Jiménez-Ortega et al., 2024; Jiménez-Ortega et al., 2023).

Once the crude extracts are obtained, they can be purified by column chromatography, using silica as the stationary phase and solvents of increasing polarity as the mobile phase to elute metabolites in fractions of different polarities. The effect of each fraction can then be evaluated and/or further purified to obtain pure crystals of the FC. Typically, the compound’s retention factor is monitored by thin-layer chromatography (TLC); if crystals or precipitates are obtained, they can be analyzed using LC-MS/MS, GC-MS/MS, NMR, X-ray diffraction, FTIR, among other techniques (Patil et al., 2023). Figure 5 shows the experimental protocol for obtaining FC from agricultural by-products, highlighting the unit operations involved.

Antibacterial activity. Two of the most common mechanisms by which FC inhibit bacterial growth are: (1) molecular and genetic damage, and (2) disruption of cellular membranes. Genetic damage occurs when FC, such as alkaloids, interact with the nitrogenous bases of bacterial nucleic acids, altering the expression of genes responsible for flagellum production and thereby reducing bacterial motility. This results in decreased growth and a reduced capacity for infection (Dusane et al., 2014).

On the other hand, damage or rupture of the bacterial cell membrane occurs through interactions with terpenoids, which partially or completely dissolve it, causing lysis and cell death (Yang et al., 2020). Agricultural and agro-industrial by-products contain antibacterial FC; however, their effectiveness will depend on the type of FC, the extraction method, the concentration, and the type of bacterium, among other factors (Table 1).

Figure 5

Terpenes can cause irreversible damage to bacterial cell membranes and walls, leaving them without adequate protection against other toxic agents. Polyphenols, on the other hand, can inhibit bacterial growth by decreasing the activity of key enzymes involved in essential biological functions (Yang et al., 2020).

Some outstanding examples include the study by Do et al. (2021), who evaluated the antibacterial activity of crude root extracts of Scutellaria baicalensis and purified baicalein (BAI). The authors observed that the bacterium Ralstonia solanacearum was more susceptible to BAI, showing greater inhibition than the control group treated with chloramphenicol (MIC of 0.019 mg mL⁻¹ and 0.000044 mg mL⁻¹, respectively). This is attributed to the presence of hydroxyl groups in BAI, which may be responsible for the inhibition. Likewise, BAI was more effective than the crude extract (up to 105-fold).

Currently, science and technology are developing new methods to maximize the extraction of FC from by-products, as these compounds are often bound to lignified polymeric structures (in stems and roots) composed of cellulose, hemicellulose, and lignin, making their extraction particularly challenging. To release them, it is necessary to break the cell wall and the ester and ether bonds between FC and the polymers so that they can dissolve in the solvent. In such cases, acidic and alkaline processes must be used, coupled with emerging extraction methods such as ultrasound-microwave techniques, among others (Santos-Zea et al., 2018; Wang et al., 2020).

Table 1

By-product	Extract	Phytochemical	Phytopathogen	MIC	Inhibition (%)	Reference
Scutellaria roots	Ethanolic	Baicalein	A. avenae subsp. Cattlyae	19 µg mL-1	75 - 94	Do et al., 2021
			A. tumefaciens
			B. glumae C. michiganensis subsp.
			michiganensis
			P. carotovara subsp.
			carotorova D. chrysanthemi
			P. syringae pv. lachrymans
			X. arboricola pruni
			P. syringae pv. actinidiae KW11
			R. solanacearum
Date palm	Aqueous	Protocatechuic acid	X. campestris	3.13 mg mL-1	100	Mrabet et al., 2017
		Tyrosol	E. amylovora
		Vanillic acid	E. toletana
		p-Coumaric acid	C. michiganensis subsp.
		Syringic acid	michiganensis
		Gallic acid	C. michiganensis subsp. insidiosus
			R. radiobacter
			P. savastanoi
			P. syringae
Pomegranate peel	Aqueous	Flavonoids y taninos	X. campestris	5 mg mL-1	100	Elshafie et al., 2021
			C. michiganensis
Banana pseudostem and marigold leaves	Aqueous	α-Terthienyl	P. syringae pv. spinacae	100 mg mL-1	37 - 40	Mitra y Paul, 2016
		Polyacetylenes	P. syringae pv. tomato
		Polythienyls
		Coumarins
Pine and olive bark, and leaves	Acetone	Terpenes	A. tumefaciens	0.41 mg mL-1	100	Badawy y Faraj, 2019
		Caryophyllene	E. carotovora
		β-Cubenene	C. fascians
		Cembrene	P. solanacearum
		Thunbergol

On the other hand, if the by-products are leaves, pulps, or bagasse, they can be extracted directly through hydrothermal treatments, since phenolic compounds and terpenes are typically located in vacuoles and trichomes, respectively. For example, thermal pretreatments can increase the extraction yield of FC. In date palm (Phoenix dactylifera), the release of polyphenols is facilitated. Extraction temperature plays a fundamental role, as higher temperatures release greater amounts of compounds such as hydroxymethylfurfural and, consequently, in most cases, greater inhibition of phytopathogens is observed. Likewise, it was reported that increasing the temperature from 140 to 160 °C reduced the MIC by up to 50% against Xanthomonas campestris, Erwinia amylovora, Clavibacter michiganensis subsp. michiganensis, C. michiganensis subsp. insidiosus, Rhizobium radiobacter, Pseudomonas savastanoi, and Pseudomonas syringae (Mrabet et al., 2017). Additionally, it has been observed that the aqueous extract of pomegranate peel (Punica granatum), rich in flavonoids and tannins, exhibited activity against X. campestris and C. michiganensis, with an MIC of 5 mg mL⁻¹. This concentration produced nearly 100% inhibition in both bacteria, similar to the controls treated with kanamycin (0.05 mg mL⁻¹) and tetracycline (0.16 mg mL⁻¹) (Elshafie et al., 2021).

It is worth mentioning that extracts from banana pseudostem (Musa paradisiaca) and marigold leaves (Tagetes erecta) showed in vivo inhibitory activity against P. syringae, reducing disease severity in tomato (S. lycopersicum), spinach (Spinacia oleracea), cucumber (Cucumis sativus), and barley (Hordeum vulgare). A 38% reduction in disease was observed at a concentration of 100 mg mL⁻¹. Although application of the extracts did not completely reduce disease severity, it did contribute to treatment when used synergistically with another extract of higher activity (Mitra and Paul, 2016). This suggests that plant extracts may serve as potential biocidal products in vivo; therefore, further research on phytotoxicity, dosage, and treatment regimens is recommended.

On the other hand, hydrophilic extracts from pine leaves and bark (Pinus spp.) and olive (Olea europaea) were shown to be rich in monoterpenes, steroids, diterpenes, sesquiterpenes, resins, and polyphenols. These extracts exhibited inhibitory activity against Agrobacterium tumefaciens, Erwinia carotovora, Corynebacterium fascians, and P. solanacearum. The most effective extract across all bacteria was olive bark, which showed the lowest MIC against C. fascians (0.41 mg mL⁻1) (Badawy and Faraj, 2019). Extracts from wine industry by-products, such as grape pomace and seeds (Vitis vinifera), obtained through emerging methods, inhibited P. syringae pv. syringae with an MIC > 1 mg mL⁻¹, lower than that of the control (dithianon), which is attributed to the presence of anthocyanins and fatty acids (Tacchini et al., 2019).

Antifungal activity. Antifungal activity is evaluated using different techniques, such as inhibition of sporulation (%), inhibition of mycelial growth (%), minimum inhibitory concentration (MIC), and minimum fungicidal concentration (MFC). As in bacteria, the mechanism by which FC inhibits fungi is also related to disruption of the fungal membrane; when it is dissolved or ruptured, internal organelles become exposed, triggering a series of cell-death pathways and leading to growth inhibition. Another mechanism occurs once FC cross the fungal membrane: they negatively affect mitochondrial cellular respiration, causing metabolic imbalance. With reduced energy availability, fungi are unable to carry out vital metabolic functions, which consequently diminishes their growth and propagation. Other mechanisms include inhibition of efflux pumps that remove intracellular toxic substances; inhibition of protein and genetic material synthesis; promotion of mitochondrial dysfunction; and inhibition of cell division (Al Aboody and Mickymaray, 2020; Peng et al., 2012).

Wine industry by-products. Grape pomace extracts are rich in anthocyanins, polyphenols, and fatty acids. However, their effectiveness depends on the extraction method (Mendoza et al., 2013; Tacchini et al., 2019). For example, grape seed extracts obtained by ultrasound contained higher amounts of FC and were effective against Sclerotinia minor and S. sclerotiorum, with an MIC > 15 µg mL⁻¹ for both fungi (Tacchini et al., 2019).

Solanum lycopersicum by-products. Hydrophilic extracts from tomato leaves and stems showed in vivo inhibition against Colletotrichum coccodes, Fusarium oxysporum f. sp. lycopersici, Glomerella cingulata, and Rhizoctonia solani. The leaf extract exhibited inhibition against R. solani, with an MIC < 0.31 mg mL⁻¹ (Kim et al., 2019). On the other hand, hydroethanolic extracts from tomato leaves were effective against Aspergillus niger (MIC 0.90 mg mL⁻¹) and Penicillium funiculosum (MIC 0.45 mg mL⁻¹). The inhibition was attributed to the presence of flavonoids and phenolic acids, which are abundant in polar solvents such as ethanol. The strongest effect was observed against P. funiculosum, with an MIC lower than that of ketoconazole (MIC 2.50 mg mL⁻¹) (Añibarro-Ortega et al., 2020).

Jatropha curcas by-products. It is well known that Jatropha is an important source of fats and oils for various industries. One of its main by-products is the seed, a structure that is resilient to conventional extraction treatments; however, it contains antifungal FC. For example, Haq et al. (2021) evaluated the methanolic extract of defatted J. curcas seeds against C. coccodes, R. solani, Bipolaris oryzae, and Fusarium fujikuroi. Among the fungi tested, B. oryzae was the most susceptible, with an MIC of 1.5 mg mL⁻¹, being even more effective than the control (amphotericin B). This activity is attributed to the presence of flavonoids, which may interact with fungal genetic material, affecting the synthesis of physiologically important proteins and reducing growth. On the other hand, Lasiodiplodia theobromae, Curvularia lunata, Fusarium semitectum, C. capsici, and C. gloeosporioides were found to be susceptible to the ethanolic extract of defatted Jatropha seed, with an MIC of 500 mg mL-1 (Saetae and Suntornsuk, 2010).

Punica granatum by-products. Pomegranate is a fruit highly valued by consumers; however, during its ripening period, large quantities of by-products such as leaves, pomace, and peels are generated, which, due to their composition, have demonstrated antifungal capacity. For example, ethanolic extract from pomegranate peel applied against F. oxysporum, A. niger, F. graminearum, F. culmorum, and A. alternata showed an MIC of 0.31 mg mL⁻¹, with flavonoids and tannins identified as the compounds responsible for the bioactivity (Hlima et al., 2019). In contrast, aqueous extracts exhibited lower activity against F. oxysporum and P. digitatum, with an MIC of 10 mg mL-1, which may be due to the lower extraction efficiency of water, a more polar solvent than ethanol (Elshafie et al., 2021).

Other extracts obtained from pomegranate by-products and evaluated against P. italicum, B. cinerea, and R. stolonifer showed mycelial growth inhibition (MGI) of 28.46% for P. italicum and 42.50% for B. cinerea and R. stolonifer. Regarding spore germination inhibition (SGI), P. italicum exhibited 17.86% inhibition, while B. cinerea and R. stolonifer showed 30.5% inhibition. With respect to the type of by-product, leaves, seeds, and peels showed SGI values of 32.16, 38.60, and 43%, and MGI values of 17.13, 29.93, and 32.25%, respectively. For the concentrations tested-500, 1,000, and 1,500 ppm-SGI values were 40.99, 49.20, and 61.78%, and MGI values were 27.05, 33.86, and 45%, respectively (Tehranifar et al., 2011). On the other hand, aqueous extraction (microwave-assisted) of pomegranate peel combined with avocado peel and seed, evaluated against P. expansum and A. niger, showed an MIC of 25 mg mL⁻¹ (Skenderidis et al., 2021).

Other by-products. Extracts obtained with various solvents-such as dichloromethane, ethyl acetate, acetone, and methanol-from hop by-products generated by the brewing industry were evaluated against F. culmorum, F. equiseti, F. semitectum, F. oxysporum, P. purpurogenum, B. cinerea, Mucor hiemalis, and A. ochraceus. Notably, F. culmorum showed the lowest MIC across all extracts (0.5 mg mL⁻¹) (Bartmańska et al., 2018).

On the other hand, wastewater and oil-free solid residues derived from lavender (Lavandula angustifolia) contained phenolic compounds and terpenes. Ethanolic extracts of both by-products exhibited antifungal activity against A. niger, A. alternata, and P. chrysogenum, with MIC values of 0.08 µg mL⁻¹ (wastewater) and 0.50 µg mL⁻¹ (solid residue). Notably, both extracts showed lower MICs than lavender essential oil (0.75 µg mL⁻¹), and the wastewater extract displayed lower MIC values than synthetic antifungals such as caspofungin (0.24 µg mL⁻¹) and kanamycin (Ciocarlan et al., 2021). The study suggests that the wastewater from essential oil distillation exhibits broad bactericidal activity, likely due to its high content of hydrophobic (terpenes) and hydrophilic (flavonoids) compounds.

Papaya seeds and leaves (Carica papaya) contain saponins, flavonoids, and carotenoids, which have demonstrated activity against Fusarium spp. and

C. gloeosporioides. Ethanolic extracts of papaya leaves showed an MIC of 0.625 mg mL⁻¹ against Fusarium spp. and >10 mg mL⁻¹ against C. gloeosporioides (Chávez-Quintal et al., 2011). Citrus peel extracts obtained by hydrodistillation were evaluated against R. solani, C. lunata, F. oxysporum, Helminthosporium oryzae, A. niger, Cladosporium herbarum, and Trichoderma viride, with the lowest MIC observed against A. niger (6.25 μL mL⁻¹) (Vasudeva and Sharma, 2012). Table 2 presents additional examples of the antifungal activity of FC from agricultural and agro-industrial by-products.

According to the 12 principles of green chemistry (Anastas and Eghbali, 2010), the production of biopesticides can be considered green, as energy consumption is minimal, waste generation is reduced, and the final products are not hazardous. Likewise, biorational products provide protection against microorganisms and insects and are effective at low concentrations. They are biodegradable and leave no residues, in contrast to chemical pesticides (Fenibo et al., 2022). Before being marketed, it is necessary to evaluate their phytotoxicity to determine appropriate doses and routes of application. However, biorational products do not exhibit toxicity in mammals when applied at the recommended concentrations. In addition, their commercialization requires compliance with strict health and safety regulations. The biorational products industry is continually growing. Some commercial successes include Aza-Direct, which contains azadirachtin; Timorex Gold, based on tea tree oil; and Regalia MAXX, formulated with Reynoutria sachalinensis extract, among others.

Table 2

By-product	Extract	Phytochemical	Phytopathogen	MIC	Inhibition (%)	Reference
Tomato leaves and stems	Hexane,	Linolenic acid	C. coccodes	<0.31 mg mL-1	51.2 - 69.8	Kim et al., 2019
	dichloromethane,	Caffeic acid	F. oxysporum f. sp.
	Acetone,		Lycopersici
	methanol		G. cingulata
			R. solani
J. curcas seed oils and extracts	Aqueous,	Flavonoids	C. coccodes	1.5 mg mL-1	80	Haq et al., 2021
	Hexane,	Saponins	R. solani
	methanol	Tannins	B. oryzae
		Steroids	F. fujikuroi
		Glycosides
J. curcas seeds	Ethanolic	Phorbol esters	F. oxysporum	500 mg L-1	50	Saetae and Suntornsuk, 2010
			L. theobromae
			C. lunata
			F. semitectum
			C. capsici
			C. gloeosporioides
Pomegranate peel (P. granatum)	Ethanolic	Flavonoids	F. oxysporum	0.312 mg mL-1	100	Hlima et al., 2019
		Anthocyanins	A. niger
			F. graminearum
			F. culmorum
			A. alternata
Pomegranate peel (P. granatum)	Aqueous	Tannins	F. oxysporum	10 mg mL-1	42	Elshafie et al., 2021
		Flavonoids	P. digitatum
		Polisacáridos	B. cinerea
Spent hops	Dichloromethane	Flavonoids	F. culmorum	0.5 mg mL-1	50	Bartmańska et al., 2018
	Ethyl acetate		F. equiseti
	Acetone		F. semitectum
	Methanol		F. oxysporum
			P. purpurogenum
			B. cinerea
			M. hiemalis
			A. ochraceus
Avocado and pomegranate peel and seed	Aqueous	Procyanidin	P. expansum	25 mg mL-1	100	Skenderidis et al., 2021
		Catechins	A. niger
		Quercetin
		Caffeoylquinic acid
		Coumaric acid
Lavender	Aqueous	Eucalyptol	A. niger	0.08 µg mL-1	100	Ciocarlan et al., 2021
		Linalool	A. alternata
		Linalool oxide	P. chrysogenum
		Terpinen-1-en-4-ol
		α-Terpineol
Pomegranate peel, leaves, and seeds	Aqueous methanol	Punicalagin	P. italicum	500 ppm	40.99	Tehranifar et al., 2011
		Ellagic acid	B. cinerea
			R. stolonifer
Grape pomace	methanol	Gallic acid	B. cinerea	35.7 µg mL-1	50	Mendoza et al., 2013
	Ethanolic	Protocatechuic acid
		Vanillic acid
		Ellagic acid,
		Quercetin
		Kaemferol
		p-Coumaric acid
		Syringic acid
		Epicatechin
		Catechin
Spent grape pomace and grape seed	Ethanolic	Anthocyanins	S. minor	>15 µg mL-1	50	Tacchini et al., 2019
		Malvidin-3-O-glucoside	S. sclerotiorum
		Delphinidin-3-O-glucoside
		Cyanidin-3-O-glucoside
Tomato leaves and stems	HidroEthanolic	p-Coumaric acid	P. funiculosum	0.45 mg mL-1	100	Añibarro-Ortega et al., 2020
		hexoside	A. niger
		5-O-Caffeoylquinic acid
		5-p-Coumaroylquinic acid
		5-O-Feruloylquinic acid
		Quercetin-pentosyl-rutinoside Rutin
		Quercetin-deoxyhexosyl-hexoside
		Kaempferol-3-O-rutinoside
Papaya leaves and seeds	Ethanolic	Triterpenes	Fusarium spp.	0.625 mg mL-1	50	Chávez-Quintal et al., 2011
		Flavonoids	C. gloeosporioides
		Alkaloids
		Saponins
Citrus peel	Aqueous	Essential oils	R. solani	6.25 µg mL-1	100	Vasudeva y Sharma, 2012
		D-Limonene	C. lunata
		(±)-Linalool	F. oxysporum
		β-Myrcene	H. oryzae
		α-Pinene	A. niger
		Sabinene	C. herbarum
		δ-3-Carene	T. viride
Pine and olive bark, and leaves	Acetone	Terpenes	B. cinerea	0.071 mg mL-1	50	Badawy y Faraj, 2019
		Caryophyllene
		β-Cubenene
		Cembrene
		Thunbergol

Regarding their toxicity, these molecules have a high LD₅₀, but being of natural origin does not mean they are non-toxic. Phytochemicals with generally higher toxicity profiles include essential oils and alkaloids in their pure state. Even commercial derivatives such as spinosad, azadirachtin, thujone, pulegone, thymol, menthol, among others, are toxic when administered at high concentrations.

The market for natural products continues to grow, and this trend is expected to continue. For example, since the 1990s, pesticide consumption in Europe has reached 460 000 t, while in the United States it has exceeded 406,000 t (Rufo et al., 2024). This suggests a constant increase in the sector, indicating that the profitability and scalability of producing biopesticides derived from agricultural by-products could represent a sound technical-industrial option.

A process that minimizes resource use and maximizes extraction yields uses response surface optimization designs, which generate quadratic equations for ANOVA analysis and comparison of treatment levels such as temperature, time (min), solid-liquid ratio, and other process variables. The analysis identifies the temperature, time, and solid-liquid ratio that hypothetically maximize FC extraction; to confirm this, it is necessary to evaluate the extraction yield under these conditions.

Most agrochemicals on the market are chemical pesticides belonging to the organochlorine, organophosphate, carbamate, and pyrethroid families. There are also some commercially manufactured products derived from natural sources-mainly essential oils or nutraceuticals-that have proven to be equally or even more effective than conventional products. However, these natural-origin products can be more expensive, which limits their use. Therefore, it is necessary to identify new, cost-effective, and readily available sources of FC, such as agricultural and agro-industrial by-products.

In Mexico, the volumes of waste generated are extremely large, as it is one of the leading producers of crops such as pepper, corn, avocado, agave, and tomato, which generate seeds, peels, fibers, leaves, and stems. From a commercial standpoint, their high availability in the region can create competitive advantages. For this reason, within a circular economy framework, the goal is to recover these by-products and subsequently obtain functional molecules for agriculture (Gopinath et al., 2018). It is worth noting that traditional disposal practices for agricultural by-products (field burning, effluent contamination, and pollution of water bodies) do not generate added value; rather, they can harm the environment and the health of workers (Koul, 2023). Mexico is one of the countries with the highest agricultural production, and thus it can take advantage of this asset to develop new industries that process residues and isolate and purify FC. However, this requires the scientific sector to promote, evaluate, and disseminate information in order to attract the attention of the private sector and enable the corresponding technology transfer for the production of biorational products.

Without a doubt, FC extracted from natural sources such as agricultural and agro-industrial residues can become sustainable and optimizable resources. Therefore, it is recommended to continue exploring new agricultural materials-such as peels and seeds-rich in phenolic compounds, primarily flavonoids, and in terpenes, whose use as potential biofungicides and biobactericides has been suggested by various studies and may support the development of commercial applications (Duque-Acevedo et al., 2020).